Cell and electrochemical device

ABSTRACT

The present disclosure provides a cell and an electrochemical device. The cell comprises: a first electrode plate comprising a first current collector and a first active material layer, a second electrode plate comprising a second current collector and a second active material layer; a first electrode tab, a second electrode tab, a separator. The first current collector has a first surface uncoated region; the second current collector has a second surface uncoated region; the first electrode tab is provided on the first surface uncoated region, the second electrode tab is provided on the second surface uncoated region. The first electrode tab and/or the second electrode tab are enlarged in length and width. When the cell is subjected to a mechanical shock, the first electrode tab and the second electrode tab are deformed to puncture the separator therebetween, so the first current collector and the second current collector are electrically connected.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Chinese patent applicationNo. 201410627615.7 filed on Nov. 10, 2014, which is incorporated hereinby reference in its entirety.

TECHNICAL FIELD OF THE PRESENT DISCLOSURE

The present disclosure relates to a field of energy storage devices, andparticularly relates to a cell and an electrochemical device.

BACKGROUND OF THE PRESENT DISCLOSURE

With the rapid development of transportation, communication andinformation industry and increasingly serious energy crisis, and withbirth and development of electric vehicles and various portable devices,it is urgent to require an alternative energy with high performance.Because a secondary lithium battery has the advantages, such as highenergy density, high cycle performance and low self-discharge rate andthe like, it becomes an ideal choice for the alternative energy as achemical power source. At present, it has been widely used in notebookcomputers, smart phones, electric tools and other consumer electronics,and has made considerable development and progress in fields of electricvehicles, energy storage batteries and the like in recent years.

The application field of the lithium-ion battery continues to expandrapidly, while the safety performance is always a key issue to beconcerned and resolved in the lithium-ion battery industry, and becomesan important factor in determining the development prospects oflithium-ion battery. Causes of safety accidents of the lithium-ionbattery include a battery internal short circuit and an external abuse.The factors associated with abuse mainly include external environmentoverheating, external short circuit, overcharge/overdischarge, andnailing, crushing, impact and other mechanical shocks. In accordancewith the level of risk, the safety accidents caused by the abovepotential safety hazards can be divided into battery swelling, breakageof packaging, smoking, firing, and explosion caused by thermal runaway.

Eliminating the potential safety hazards and reducing the level of riskare effective ways to improve the safety performance of the lithium-ionbattery. And, increasing lengths of a part of an aluminum foil currentcollector not provided with a positive active material layer and a partof a copper foil current collector not provided with a negative activematerial layer of a wound-type cell at an ending part is one techniquewidely used currently. Although the redundant part of the aluminum foilcurrent collector not provided with the positive active material layerand the redundant part of the copper foil current collector not providedwith the negative active material layer of the wound-type cell at theending part can surround the cell, internal short circuits can beeffectively converted to external short circuits in the cases ofnailing, crushing, impact, so as to avoid thermal runaway occurringinside the lithium-ion battery caused by too large current, and in turnto reduce serious accidents such as burning and explosions. But atpresent the biggest obstacle in such a technology is at the expense of avolumetric specific energy of the battery as a precondition.

SUMMARY OF THE PRESENT DISCLOSURE

In view of the problem existing in the background, an object of thepresent disclosure is to provide a cell and an electrochemical device,which improve the safety performance of the cell.

In order to achieve the above object, in a first aspect, the presentdisclosure provides a cell, which comprises: a first electrode platecomprising a first current collector and a first active material layerwhich is selectively provided on a surface of the first currentcollector and contains a first active material; a second electrode plateopposite to the first electrode plate in electric polarity, comprising asecond current collector and a second active material layer which isselectively provided on a surface of the second current collector andcontains a second active material; a first electrode tab provided andelectrically connected to the first current collector of the firstelectrode plate; a second electrode tab provided and electricallyconnected to the second current collector of the second electrode plate;and a separator provided between the first electrode plate and thesecond electrode plate. The surface of the first current collector has apart which is not provided with the first active material layer thereonand this part is defined as a first surface uncoated region; the surfaceof the second current collector has a part which is not provided withthe second active material layer thereon and this part is defined as asecond surface uncoated region; the first electrode tab is provided onthe first surface uncoated region and the second electrode tab isprovided on the second surface uncoated region. The first electrode tabextends toward two opposite transverse edges of the first surfaceuncoated region along a width direction and one side edge positionedoutside in the width direction is close to one corresponding transverseedge of the first surface uncoated region, and the first electrode tabextends toward two opposite longitudinal edges of the first surfaceuncoated region along a length direction and two outer side edges in thelength direction are close to the two longitudinal edges of the firstsurface uncoated region, respectively; and/or the second electrode tabextends toward two opposite transverse edges of the second surfaceuncoated region along the width direction and one side edge positionedoutside in the width direction is close to one corresponding transverseedge of the second surface uncoated region, and the second electrode tabextends toward two opposite longitudinal edges of the second surfaceuncoated region along the length direction and two outer side edges inthe length direction are close to the two longitudinal edges of thesecond surface uncoated region, respectively. The first electrode taband the second electrode tab are spaced apart from each other in thewidth direction, and the separator is presented between the firstelectrode tab and the second electrode tab. When the cell is subjectedto a mechanical shock, the first electrode tab and the second electrodetab are deformed to puncture the separator between the first electrodetab and the second electrode tab such that the first current collectorand the second current collector are electrically connected.

In order to achieve the above object, in a second aspect, the presentdisclosure provides an electrochemical device, which comprises the cellaccording to the first aspect of the present disclosure.

The present disclosure has the following beneficial effects:

In the present disclosure, the first electrode tab extends toward twoopposite transverse edges of the first surface uncoated region along thewidth direction and one side edge positioned outside in the widthdirection is close to one corresponding transverse edge of the firstsurface uncoated region, and the first electrode tab extends toward twoopposite longitudinal edges of the first surface uncoated region alongthe length direction and two outer side edges in the length directionare close to the two longitudinal edges of the first surface uncoatedregion, respectively; and/or the second electrode tab extends toward twoopposite transverse edges of the second surface uncoated region alongthe width direction and one side edge positioned outside in the widthdirection is close to one corresponding transverse edge of the secondsurface uncoated region, and the second electrode tab extends toward twoopposite longitudinal edges of the second surface uncoated region alongthe length direction and two outer side edges in the length directionare close to the two longitudinal edges of the second surface uncoatedregion, respectively. Therefore, compared with the cell in the priorart, the first electrode tab and/or the second electrode tab of the cellof the present disclosure are/is enlarged in length and width, when thecell is subjected to a mechanical shock (for example, nailing, crushing,impact and the like), the first electrode tab and/or the secondelectrode tab which are/is enlarged in length and width are deformed topuncture the separator between the first electrode tab and the secondelectrode tab such that the first current collector and the secondcurrent collector are electrically connected, so that an internal shortcircuit which occurs inside the cell is converted to an external shortcircuit, an uncontrollable thermal runaway caused by the internal shortcircuit inside the cell is converted to a temperate controllableexternal short circuit, thereby reducing the occurrence risk of badaccidents such as burning and explosions, and greatly improving thesafety performance of the cell.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a cell in the prior art;

FIG. 2 is a partial perspective view taken along a line A-A of FIG. 1,for the sake of clarity, a part of a profile of a second electrode tabis shown by a dotted line in a simplified manner;

FIG. 3 is a simplified top view along FIG. 2, for the sake of clarity,the profile of the second electrode plate is shown by a dotted line in asimplified manner;

FIG. 4 is a plan view of the cell according to the present disclosure;

FIG. 5 is a partial perspective view taken along a line B-B of FIG. 4,for the sake of clarity, a part of the profile of the second electrodetab is shown by a dotted line in a simplified manner;

FIG. 6 is a simplified top view along FIG. 5, for the sake of clarity,the profile of the second electrode plate is shown by a dotted line in asimplified manner;

FIG. 7 is a view of an alternative embodiment similar to FIG. 6;

FIG. 8 is a view of an alternative embodiment similar to FIG. 7;

FIG. 9 is a view of an alternative embodiment similar to FIG. 8;

FIG. 10 is a view of an alternative embodiment similar to FIG. 9;

FIG. 11 is a view of an alternative embodiment similar to FIG. 10;

FIG. 12 is a view of an alternative embodiment similar to FIG. 11;

FIG. 13 is a view of an alternative embodiment similar to FIG. 12;

FIG. 14 is a view of an alternative embodiment similar to FIG. 13;

FIG. 15 is a view of an alternative embodiment similar to FIG. 14;

FIG. 16 is a view of an alternative embodiment similar to FIG. 15;

FIG. 17 is a view of an alternative embodiment similar to FIG. 16.

Reference numerals of the embodiments are represented as follows:

-   1 first electrode plate-   11 first current collector-   S11 surface-   B11 first surface uncoated region-   TE11 transverse edge-   LE11 longitudinal edge-   12 first active material layer-   2 second electrode plate-   21 second current collector-   S21 surface-   B21 second surface uncoated region-   TE21 transverse edge-   LE21 longitudinal edge-   22 second active material layer-   3 first electrode tab-   31 side edge-   32 outer side edge-   4 second electrode tab-   41 side edge-   42 outer side edge-   5 separator-   W width direction-   L length direction-   T thickness direction-   P1 first protruding portion-   P2 second protruding portion-   R1 first recessing portion-   R2 second recessing portion

DETAILED DESCRIPTION

Hereinafter a cell and electrochemical device according to the presentdisclosure will be described in detail in combination with the Figures.

Firstly a cell according to a first aspect of the present disclosurewill be described.

Referring to FIGS. 3-15, a cell according to a first aspect of thepresent disclosure comprises: a first electrode plate 1 comprising afirst current collector 11 and a first active material layer 12 which isselectively provided on a surface S11 of the first current collector 11and contains a first active material; a second electrode plate 2opposite to the first electrode plate 1 in electric polarity, comprisinga second current collector 21 and a second active material layer 22which is selectively provided on a surface S21 of the second currentcollector 21 and contains a second active material; a first electrodetab 3 provided and electrically connected to the first current collector11 of the first electrode plate 1; a second electrode tab 4 provided andelectrically connected to the second current collector 21 of the secondelectrode plate 2; and a separator 5 provided between the firstelectrode plate 1 and the second electrode plate 2. The surface S11 ofthe first current collector 11 has a part which is not provided with thefirst active material layer 12 thereon and this part is defined as afirst surface uncoated region B11; the surface S21 of the second currentcollector 21 has a part which is not provided with the second activematerial layer 22 thereon and this part is defined as a second surfaceuncoated region B21; the first electrode tab 3 is provided on the firstsurface uncoated region B11 and the second electrode tab 4 is providedon the second surface uncoated region B21; the first electrode tab 3extends toward two opposite transverse edges TE11 of the first surfaceuncoated region B11 along a width direction W and one side edge 31positioned outside in the width direction W is close to onecorresponding transverse edge TE11 of the first surface uncoated regionB11, and the first electrode tab 3 extends toward two oppositelongitudinal edges LE11 of the first surface uncoated region B11 along alength direction L and two outer side edges 32 in the length direction Lare close to the two longitudinal edges LE11 of the first surfaceuncoated region B11, respectively; and/or the second electrode tab 4extends toward two opposite transverse edges TE21 of the second surfaceuncoated region B21 along the width direction W and one side edge 41positioned outside in the width direction W is close to onecorresponding transverse edge TE21 of the second surface uncoated regionB21, and the second electrode tab 4 extends toward two oppositelongitudinal edges LE21 of the second surface uncoated region B21 alongthe length direction L and two outer side edges 42 in the lengthdirection L are close to the two longitudinal edges LE21 of the secondsurface uncoated region B21, respectively; the first electrode tab 3 andthe second electrode tab 4 are spaced apart from each other in the widthdirection W, and the separator 5 is presented between the firstelectrode tab 3 and the second electrode tab 4. When the cell issubjected to a mechanical shock, the first electrode tab 3 and thesecond electrode tab 4 are deformed to puncture the separator 5 betweenthe first electrode tab 3 and the second electrode tab 4 such that thefirst current collector 11 and the second current collector 21 areelectrically connected. Here, it should be noted that, the use of a termof “and/or” represents a mutual relationship between that the firstelectrode tab 3 is provided on the first surface uncoated region B11(that is the first current collector 11) and that the second electrodetab 4 is provided on the second surface uncoated region B21 (that is thesecond current collector 21). Specifically, because the first electrodetab 3 and the first current collector 11 can be integrally formed orseparately formed and the second electrode tab 4 and the second currentcollector 21 can be integrally formed or separately formed, when thefirst electrode tab 3 and the first current collector 11 are integrallyformed, the second electrode tab 4 and the second current collector 21must be separately formed; when the second electrode tab 4 and thesecond current collector 21 are integrally formed, the first electrodetab 3 and the first current collector 11 must be separately formed; whenthe first electrode tab 3 and the first current collector 11 areseparately formed, the second electrode tab 4 and the second currentcollector 21 may be separately formed. However, that the first electrodetab 3 and the first current collector 11 are integrally formed and thatthe second electrode tab 4 and the second current collector 21 areintegrally formed can not exist at the same time.

Here, it should be noted that, that the first active material layer 12is selectively provided on the surface S11 of the first currentcollector 11 refers to that one surface S11 of the first currentcollector 11 is entirely provided with the first active material layer12, or one surface S11 of the first current collector 11 is partlyprovided with the first active material layer 12. Similarly, that thesecond active material layer 22 is selectively provided on the surfaceS21 of the second current collector 21 refers to that one surface S21 ofthe second current collector 21 is entirely provided with the secondactive material layer 22 or one surface S21 of the second currentcollector 21 is partly provided with the second active material layer22. Of course, as long as the surface S11 of the first current collector11 has a part which is not provided with the first active material layer12 thereon and the surface S21 of the second current collector 21 has apart which is not provided with the second active material layer 22thereon and these two parts are adjacent and opposite.

Here, it should be noted that, that the first current collector 11 andthe second current collector 21 are electrically connected may be thatthe first surface uncoated region B11 of the first current collector 11on which the first electrode tab 3 is provided is in direct contact withthe second surface uncoated region B21 of the second current collector21 on which the second electrode tab 4 is provided, may also be that thefirst electrode tab 3 is in direct contact with the second surfaceuncoated region B21 of the second current collector 21 on which thesecond electrode tab 4 is provided, may also be that the first surfaceuncoated region B11 of the first current collector 11 on which the firstelectrode tab 3 is provided is in direct contact with the secondelectrode tab 4, may also be that the first electrode tab 3 is incontact with the second electrode tab 4.

Compared with the cell in the prior art (referring to FIGS. 1-3), thefirst electrode tab 3 and the second electrode tab 4 of the cell of thepresent disclosure (referring to FIGS. 4-17) are enlarged in length andwidth, when the cell is subjected to a mechanical shock (for example,nailing, crushing, impact and the like), the first electrode tab 3 andthe second electrode tab 4 which are enlarged in length and width aredeformed to puncture the separator 5 between the first electrode tab 3and the second electrode tab 4 such that the first current collector 11and the second current collector 21 are electrically connected, so thatan internal short circuit which occurs inside the cell is converted toan external short circuit, an uncontrollable thermal runaway caused bythe internal short circuit inside the cell is converted to a temperatecontrollable external short circuit, thereby reducing the occurrencerisk of bad accidents such as burning and explosions, and greatlyimproving the safety performance of the cell.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the first electrode plate 1 may be a positiveelectrode plate or a negative electrode plate, the first currentcollector 11 of the first electrode plate 1 is correspondingly apositive current collector or a negative current collector, the firstelectrode tab 3 is correspondingly a positive electrode tab or anegative electrode tab; the second electrode plate 2 is correspondinglya negative electrode plate or a positive electrode plate, the secondcurrent collector 21 of the second electrode plate 2 is correspondinglya negative current collector or a positive current collector, the secondelectrode tab 4 is correspondingly a negative electrode tab or apositive electrode tab.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the negative current collector may be a copper foil,the negative electrode tab may be a nickel sheet.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the positive current collector may be an aluminumfoil , the positive electrode tab may be an aluminium sheet.

In an embodiment of the cell according to the first aspect of thepresent disclosure, referring to FIG. 4, the cell is a wound-type cell,the first surface uncoated region B11 of the first current collector 11on which the first electrode tab 3 is provided and the second surfaceuncoated region B21 of the second current collector 21 on which thesecond electrode tab 4 is provided are positioned at a winding-startedpart of the wound-type cell (referring to FIG. 4 and FIG. 5), awinding-ended part (not shown), and parts other than the winding-startedpart and the winding-ended part (not shown). Although the figures onlyillustrate the situations that the first surface uncoated region B11 ofthe first current collector 11 on which the first electrode tab 3 isprovided and the second surface uncoated region B21 of the secondcurrent collector 21 on which the second electrode tab 4 is provided arepositioned at the winding-started part of the wound-type cell, but thepresent disclosure is not limited to that, positions of the firstsurface uncoated region B11 of the first current collector 11 on whichthe first electrode tab 3 is provided and the second surface uncoatedregion B21 of the second current collector 21 on which the secondelectrode tab 4 is provided can be determined according to a practicalsituation. In an embodiment, referring to FIG. 4 and FIG. 5, at thewinding-started part, two surfaces of the first current collector 11 ata position where the first electrode tab 3 is provided are not providedwith the first active material layer 12 (that is the two surfaces bothhave the first surface uncoated regions B11), two surfaces of the secondcurrent collector 21 at a position where the second electrode tab 4 isprovided are not provided with the second active material layer 22 (thatis the two surfaces both have the second surface uncoated regions B21),but the present disclosure is not limited to that. One surface of thefirst current collector 11 at a position where the first electrode tab 3is provided can not be provided with the first active material layer 12either, one surface of the second current collector 21 at a positionwhere the second electrode tab 4 is provided can not be provided withthe second active material layer 22 either, as long as the surface S11of the first current collector 11 has a part which is not provided withthe first active material layer 12 thereon and the surface S21 of thesecond current collector 21 has a part which is not provided with thesecond active material layer 22 thereon, and these two parts areadjacent and opposite.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the cell is a laminated-type cell (not shown), twosurfaces of the first current collector 11 at a position where the firstelectrode tab 3 is provided are not provided with the first activematerial layer 12, two surfaces of the second current collector 21 at aposition where the second electrode tab 4 is provided are not providedwith the second active material layer 22.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the cell is a wound and laminated-type cell (notshown), when started with winding, the first surface uncoated region B11of the first current collector 11 on which the first electrode tab 3 isprovided and the second surface uncoated region B21 of the secondcurrent collector 21 on which the second electrode tab 4 is provided arepositioned at the winding-started part, and two surfaces of the firstcurrent collector 11 at a position where the first electrode tab 3 isprovided are not provided with the first active material layer 12, twosurfaces of the second current collector 21 at a position where thesecond electrode tab 4 is provided are not provided with the secondactive material layer 22.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the cell is a wound and laminated-type cell, whenstarted with laminating, the first surface uncoated region B11 of thefirst current collector 11 on which the first electrode tab 3 isprovided and the second surface uncoated region B21 of the secondcurrent collector 21 on which the second electrode tab 4 is provided arepositioned at the winding-ended part, and two surfaces of the firstcurrent collector 11 at a position where the first electrode tab 3 isprovided are not provided with the first active material layer 12, twosurfaces of the second current collector 21 at a position where thesecond electrode tab 4 is provided are not provided with the secondactive material layer 22.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the first electrode tab 3 may be welded to the firstcurrent collector 11 of the first electrode plate 1 or may be formed bycutting the first current collector 11 of the first electrode plate 1;and/or the second electrode tab 4 may be welded to the second currentcollector 21 of the second electrode plate 2 or may be formed by cuttingthe second current collector 21 of the second electrode plate 2.However, it should be noted that, the first electrode tab 3 and thesecond electrode tab 4 can not be formed by cutting at the same time. Inother words, when the first electrode tab 3 is formed by cutting, thesecond electrode tab 4 is formed by welding; when the second electrodetab 4 is formed by cutting, the first electrode tab 3 is formed bywelding. But both the first electrode tab 3 and the second electrode tab4 can be formed by welding.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the first electrode tab 3 and the second electrodetab 4 each have a thickness of TT, and 5 μm≦TT≦100 μm; the firstelectrode tab 3 and the second electrode tab 4 each have a length of LT,and 10 mm≦LT≦500 mm; the first electrode tab 3 and the second electrodetab 4 each have a width of WT, and 2 mm≦WT≦250 mm.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a minimum distance between the one side edge 31 ofthe first electrode tab 3 positioned outside in the width direction Wand the one corresponding transverse edge TE11 of the first surfaceuncoated region B11 is 3 mm.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a minimum distance between the each outer side edge32 of the first electrode tab 3 in the length direction L and the onecorresponding longitudinal edge LE11 of the first surface uncoatedregion B11 is 3 mm.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a minimum distance between the one side edge 41 ofthe second electrode tab 4 positioned outside in the width direction Wand the one corresponding transverse edge TE21 of the second surfaceuncoated region B21 is 3 mm.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a minimum distance between the each outer side edge42 of the second electrode tab 4 in the length direction L and the onecorresponding longitudinal edge LE21 of the second surface uncoatedregion B21 is 3 mm.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a distance between the one side edge 31 of the firstelectrode tab 3 positioned inside in the width direction W and the oneside edge 41 of the second electrode tab 4 positioned inside in thewidth direction W is 1 mm-5 mm in the width direction W.

In an embodiment of the cell according to the first aspect of thepresent disclosure, referring to FIG. 8, the one side edge 31 of thefirst electrode tab 3 positioned inside in the width direction W and theone side edge 41 of the second electrode tab 4 positioned inside in thewidth direction W are respectively provided with a plurality of firstprotruding portions P1 and a plurality of second recessing portions R2which form a jagged shape and are matched in form of concave-convex.

In an embodiment of the cell according to the first aspect of thepresent disclosure, referring to FIG. 7 and FIGS. 11-17, the one sideedge 31 of the first electrode tab 3 positioned inside in the widthdirection W and the one side edge 41 of the second electrode tab 4positioned inside in the width direction W are respectively providedwith a plurality of first recessing portions R1 and a plurality ofsecond protruding portions P2 which form a jagged shape and are matchedin form of concave-convex.

In an embodiment of the cell according to the first aspect of thepresent disclosure, referring to FIG. 9, the one side edge 31 of thefirst electrode tab 3 positioned inside in the width direction W and theone side edge 41 of the second electrode tab 4 positioned inside in thewidth direction W are respectively provided with a plurality of firstprotruding portions P1 and a plurality of second protruding portions P2which form a jagged shape and are matched in clearance fit.

In an embodiment of the cell according to the first aspect of thepresent disclosure, referring to FIG. 10, the one side edge 31 of thefirst electrode tab 3 positioned inside in the width direction W and theone side edge 41 of the second electrode tab 4 positioned inside in thewidth direction W are respectively provided with a plurality of firstrecessing portions R1 and a plurality of second recessing portions R2which form a jagged shape and are matched in clearance fit.

In an embodiment of the cell according to the first aspect of thepresent disclosure, the first electrode tab 3 and the first protrudingportion P1 or the first recessing portion R1 provided on the firstelectrode tab 3 are integrally formed; the second electrode tab 4 andthe second protruding portion P2 or the second recessing portion R2provided on the second electrode tab 4 are integrally formed.

In an embodiment of the cell according to the first aspect of thepresent disclosure, a shape of the first protruding portion P1, a shapeof the first recessing portion R1, a shape of the second protrudingportion P2, a shape of the second recessing portion R2 each are one of arectangle (referring to FIGS. 7-10), a square (referring to FIG. 11 andFIG. 12), a triangle (referring to FIG. 15), a semicircle (referring toFIG. 16), a trapezoid (referring to FIG. 17), a polygon with more thanfour sides (referring to FIG. 13 and FIG. 14, which is a pyramid shapewith a base). Shapes of the first protruding portion P1, the firstrecessing portion R1, the second protruding portion P2, the secondrecessing portion R2 are not limited to the examples shown in thefigures, changes can be made according to the spirit and gist of thepresent disclosure.

In an embodiment of the cell according to the first aspect of thepresent disclosure, at least one of the one side edge 31 of the firstelectrode tab 3 positioned inside in the width direction W and the oneside edge 41 of the second electrode tab 4 positioned inside in thewidth direction W is flat. In an embodiment, referring to FIG. 5 andFIG. 6, one side edge 31 of the first electrode tab 3 positioned insidein the width direction W and one side edge 41 of the second electrodetab 4 positioned inside in the width direction W are both flat.

Next, an electrochemical device according to a second aspect of thepresent disclosure will be described.

The electrochemical device according to the second aspect of the presentdisclosure comprises the cell according to the first aspect of thepresent disclosure.

In an embodiment of the electrochemical device according to the secondaspect of the present disclosure, the electrochemical device may be abattery or a capacitor.

What is claimed is:
 1. A cell, comprising: a first electrode plate (1)comprising a first current collector (11) and a first active materiallayer (12) which is selectively provided on a surface (S11) of the firstcurrent collector (11) and contains a first active material; a secondelectrode plate (2) opposite to the first electrode plate (1) inelectric polarity, comprising a second current collector (21) and asecond active material layer (22) which is selectively provided on asurface (S21) of the second current collector (21) and contains a secondactive material; a first electrode tab (3) provided and electricallyconnected to the first current collector (11) of the first electrodeplate (1); a second electrode tab (4) provided and electricallyconnected to the second current collector (21) of the second electrodeplate (2); and a separator (5) provided between the first electrodeplate (1) and the second electrode plate (2); the surface (S11) of thefirst current collector (11) having a part which is not provided withthe first active material layer (12) thereon and this part being definedas a first surface uncoated region (B11); the surface (S21) of thesecond current collector (21) having a part which is not provided withthe second active material layer (22) thereon and this part beingdefined as a second surface uncoated region (B21); the first electrodetab (3) being provided on the first surface uncoated region (B11) andthe second electrode tab (4) being provided on the second surfaceuncoated region (B21); the first electrode tab (3) extending toward twoopposite transverse edges (TE11) of the first surface uncoated region(B11) along a width direction (W) and one side edge (31) positionedoutside in the width direction (W) being close to one correspondingtransverse edge (TE11) of the first surface uncoated region (B11), andthe first electrode tab (3) extending toward two opposite longitudinaledges (LE11) of the first surface uncoated region (B11) along a lengthdirection (L) and two outer side edges (32) in the length direction (L)being close to the two longitudinal edges (LE11) of the first surfaceuncoated region (B11), respectively; and/or the second electrode tab (4)extending toward two opposite transverse edges (TE21) of the secondsurface uncoated region (B21) along the width direction (W) and one sideedge (41) positioned outside in the width direction (W) being close toone corresponding transverse edge (TE21) of the second surface uncoatedregion (B21), and the second electrode tab (4) extending toward twoopposite longitudinal edges (LE21) of the second surface uncoated region(B21) along the length direction (L) and two outer side edges (42) inthe length direction (L) being close to the two longitudinal edges(LE21) of the second surface uncoated region (B21), respectively; thefirst electrode tab (3) and the second electrode tab (4) being spacedapart from each other in the width direction (W), and the separator (5)being presented between the first electrode tab (3) and the secondelectrode tab (4); when the cell is subjected to a mechanical shock, thefirst electrode tab (3) and the second electrode tab (4) being deformedto puncture the separator (5) between the first electrode tab (3) andthe second electrode tab (4) such that the first current collector (11)and the second current collector (21) being electrically connected. 2.The cell according to claim 1, wherein the first electrode tab (3) iswelded to the first current collector (11) of the first electrode plate(1) or is formed by cutting the first current collector (11) of thefirst electrode plate (1); and/or the second electrode tab (4) is weldedto the second current collector (21) of the second electrode plate (2)or is formed by cutting the second current collector (21) of the secondelectrode plate (2).
 3. The cell according to claim 1, wherein the firstelectrode tab (3) and the second electrode tab (4) each have a thicknessof TT, and 5 μm≦TT≦100 μm; the first electrode tab (3) and the secondelectrode tab (4) each have a length of LT, and 10 mm≦LT≦500 mm; thefirst electrode tab (3) and the second electrode tab (4) each have awidth of WT, and 2 mm≦WT≦250 mm.
 4. The cell according to claim 1,wherein a minimum distance between the one side edge (31) of the firstelectrode tab (3) positioned outside in the width direction (W) and theone corresponding transverse edge (TE11) of the first surface uncoatedregion (B11) is 3 mm; a minimum distance between the each outer sideedge (32) of the first electrode tab (3) in the length direction (L) andthe one corresponding longitudinal edge (LE11) of the first surfaceuncoated region (B11) is 3 mm; a minimum distance between the one sideedge (41) of the second electrode tab (4) positioned outside in thewidth direction (W) and the one corresponding transverse edge (TE21) ofthe second surface uncoated region (B21) is 3 mm; a minimum distancebetween the each outer side edge (42) of the second electrode tab (4) inthe length direction (L) and the one corresponding longitudinal edge(LE21) of the second surface uncoated region (B21) is 3 mm.
 5. The cellaccording to claim 1, wherein a distance between the one side edge (31)of the first electrode tab (3) positioned inside in the width direction(W) and the one side edge (41) of the second electrode tab (4)positioned inside in the width direction (W) is 1 mm-5 mm in the widthdirection (W).
 6. The cell according to claim 1, wherein the one sideedge (31) of the first electrode tab (3) positioned inside in the widthdirection (W) and the one side edge (41) of the second electrode tab (4)positioned inside in the width direction (W) are respectively providedwith a plurality of first protruding portions (P1) and a plurality ofsecond recessing portions (R2) which form a jagged shape and are matchedin form of concave-convex, or the one side edge (31) of the firstelectrode tab (3) positioned inside in the width direction (W) and theone side edge (41) of the second electrode tab (4) positioned inside inthe width direction (W) are respectively provided with a plurality offirst recessing portions (R1) and a plurality of second protrudingportions (P2) which form a jagged shape and are matched in form ofconcave-convex, or the one side edge (31) of the first electrode tab (3)positioned inside in the width direction (W) and the one side edge (41)of the second electrode tab (4) positioned inside in the width direction(W) are respectively provided with a plurality of first protrudingportions (P1) and a plurality of second protruding portions (P2) whichform a jagged shape and are matched in clearance fit, or the one sideedge (31) of the first electrode tab (3) positioned inside in the widthdirection (W) and the one side edge (41) of the second electrode tab (4)positioned inside in the width direction (W) are respectively providedwith a plurality of first recessing portions (R1) and a plurality ofsecond recessing portions (R2) which form a jagged shape and are matchedin clearance fit.
 7. The cell according to claim 6, wherein the firstelectrode tab (3) and the first protruding portion (P1) or the firstrecessing portion (R1) provided on the first electrode tab (3) areintegrally formed; the second electrode tab (4) and the secondprotruding portion (P2) or the second recessing portion (R2) provided onthe second electrode tab (4) are integrally formed.
 8. The cellaccording to claim 6, wherein a shape of the first protruding portion(P1), a shape of the first recessing portion (R1), a shape of the secondprotruding portion (P2), a shape of the second recessing portion (R2)each are one of a rectangle, a square, a triangle, a semicircle, atrapezoid, a polygon with more than four sides.
 9. The cell according toclaim 1, wherein at least one of the one side edge (31) of the firstelectrode tab (3) positioned inside in the width direction (W) and theone side edge (41) of the second electrode tab (4) positioned inside inthe width direction (W) is flat.
 10. An electrochemical device,comprising: a cell, comprising: a first electrode plate (1) comprising afirst current collector (11) and a first active material layer (12)which is selectively provided on a surface (S11) of the first currentcollector (11) and contains a first active material; a second electrodeplate (2) opposite to the first electrode plate (1) in electricpolarity, comprising a second current collector (21) and a second activematerial layer (22) which is selectively provided on a surface (S21) ofthe second current collector (21) and contains a second active material;a first electrode tab (3) provided and electrically connected to thefirst current collector (11) of the first electrode plate (1); a secondelectrode tab (4) provided and electrically connected to the secondcurrent collector (21) of the second electrode plate (2); and aseparator (5) provided between the first electrode plate (1) and thesecond electrode plate (2); the surface (S11) of the first currentcollector (11) having a part which is not provided with the first activematerial layer (12) thereon and this part being defined as a firstsurface uncoated region (B11); the surface (S21) of the second currentcollector (21) having a part which is not provided with the secondactive material layer (22) thereon and this part being defined as asecond surface uncoated region (B21); the first electrode tab (3) beingprovided on the first surface uncoated region (B11) and the secondelectrode tab (4) being provided on the second surface uncoated region(B21); the first electrode tab (3) extending toward two oppositetransverse edges (TE11) of the first surface uncoated region (B11) alonga width direction (W) and one side edge (31) positioned outside in thewidth direction (W) being close to one corresponding transverse edge(TE11) of the first surface uncoated region (B11), and the firstelectrode tab (3) extending toward two opposite longitudinal edges(LE11) of the first surface uncoated region (B11) along a lengthdirection (L) and two outer side edges (32) in the length direction (L)being close to the two longitudinal edges (LE11) of the first surfaceuncoated region (B11), respectively; and/or the second electrode tab (4)extending toward two opposite transverse edges (TE21) of the secondsurface uncoated region (B21) along the width direction (W) and one sideedge (41) positioned outside in the width direction (W) being close toone corresponding transverse edge (TE21) of the second surface uncoatedregion (B21), and the second electrode tab (4) extending toward twoopposite longitudinal edges (LE21) of the second surface uncoated region(B21) along the length direction (L) and two outer side edges (42) inthe length direction (L) being close to the two longitudinal edges(LE21) of the second surface uncoated region (B21), respectively; thefirst electrode tab (3) and the second electrode tab (4) being spacedapart from each other in the width direction (W), and the separator (5)being presented between the first electrode tab (3) and the secondelectrode tab (4); when the cell is subjected to a mechanical shock, thefirst electrode tab (3) and the second electrode tab (4) being deformedto puncture the separator (5) between the first electrode tab (3) andthe second electrode tab (4) such that the first current collector (11)and the second current collector (21) being electrically connected. 11.The electrochemical device according to claim 10, wherein the firstelectrode tab (3) is welded to the first current collector (11) of thefirst electrode plate (1) or is formed by cutting the first currentcollector (11) of the first electrode plate (1); and/or the secondelectrode tab (4) is welded to the second current collector (21) of thesecond electrode plate (2) or is formed by cutting the second currentcollector (21) of the second electrode plate (2).
 12. Theelectrochemical device according to claim 10, wherein the firstelectrode tab (3) and the second electrode tab (4) each have a thicknessof TT, and 5 μm≦TT≦100 μm; the first electrode tab (3) and the secondelectrode tab (4) each have a length of LT, and 10 mm≦LT≦500 mm; thefirst electrode tab (3) and the second electrode tab (4) each have awidth of WT, and 2 mm≦WT≦250 mm.
 13. The electrochemical deviceaccording to claim 10, wherein a minimum distance between the one sideedge (31) of the first electrode tab (3) positioned outside in the widthdirection (W) and the one corresponding transverse edge (TE11) of thefirst surface uncoated region (B11) is 3 mm; a minimum distance betweenthe each outer side edge (32) of the first electrode tab (3) in thelength direction (L) and the one corresponding longitudinal edge (LE11)of the first surface uncoated region (B11) is 3 mm; a minimum distancebetween the one side edge (41) of the second electrode tab (4)positioned outside in the width direction (W) and the one correspondingtransverse edge (TE21) of the second surface uncoated region (B21) is 3mm; a minimum distance between the each outer side edge (42) of thesecond electrode tab (4) in the length direction (L) and the onecorresponding longitudinal edge (LE21) of the second surface uncoatedregion (B21) is 3 mm.
 14. The electrochemical device according to claim10, wherein a distance between the one side edge (31) of the firstelectrode tab (3) positioned inside in the width direction (W) and theone side edge (41) of the second electrode tab (4) positioned inside inthe width direction (W) is 1 mm-5 mm in the width direction (W).
 15. Theelectrochemical device according to claim 10, wherein the one side edge(31) of the first electrode tab (3) positioned inside in the widthdirection (W) and the one side edge (41) of the second electrode tab (4)positioned inside in the width direction (W) are respectively providedwith a plurality of first protruding portions (P1) and a plurality ofsecond recessing portions (R2) which form a jagged shape and are matchedin form of concave-convex, or the one side edge (31) of the firstelectrode tab (3) positioned inside in the width direction (W) and theone side edge (41) of the second electrode tab (4) positioned inside inthe width direction (W) are respectively provided with a plurality offirst recessing portions (R1) and a plurality of second protrudingportions (P2) which form a jagged shape and are matched in form ofconcave-convex, or the one side edge (31) of the first electrode tab (3)positioned inside in the width direction (W) and the one side edge (41)of the second electrode tab (4) positioned inside in the width direction(W) are respectively provided with a plurality of first protrudingportions (P1) and a plurality of second protruding portions (P2) whichform a jagged shape and are matched in clearance fit, or the one sideedge (31) of the first electrode tab (3) positioned inside in the widthdirection (W) and the one side edge (41) of the second electrode tab (4)positioned inside in the width direction (W) are respectively providedwith a plurality of first recessing portions (R1) and a plurality ofsecond recessing portions (R2) which form a jagged shape and are matchedin clearance fit.
 16. The electrochemical device according to claim 15,wherein first electrode tab (3) and the first protruding portion (P1) orthe first recessing portion (R1) provided on the first electrode tab (3)are integrally formed; the second electrode tab (4) and the secondprotruding portion (P2) or the second recessing portion (R2) provided onthe second electrode tab (4) are integrally formed.
 17. Theelectrochemical device according to claim 15, wherein a shape of thefirst protruding portion (P1), a shape of the first recessing portion(R1), a shape of the second protruding portion (P2), a shape of thesecond recessing portion (R2) each are one of a rectangle, a square, atriangle, a semicircle, a trapezoid, a polygon with more than foursides.
 18. The electrochemical device according to claim 10, wherein atleast one of the one side edge (31) of the first electrode tab (3)positioned inside in the width direction (W) and the one side edge (41)of the second electrode tab (4) positioned inside in the width direction(W) is flat.